Fix false positives in closure_spacing

Fixes #3270

CHANGELOG.md

@@ -54,6 +54,11 @@
   [Marcelo Fabri](https://github.com/marcelofabri)
   [#3186](https://github.com/realm/SwiftLint/issues/3186)
 
+* Fix false positives in `closure_spacing` rule reported in 
+  non-closures expressions.  
+  [Marcelo Fabri](https://github.com/marcelofabri)
+  [#3270](https://github.com/realm/SwiftLint/issues/3270)
+
 ## 0.39.2: Stay Home
 
 This is the last release to support building with Swift 5.0.x.

Source/SwiftLintFramework/Rules/Style/ClosureSpacingRule.swift

@@ -30,7 +30,17 @@ public struct ClosureSpacingRule: CorrectableRule, ConfigurationProviderRule, Op
             Example("[].map ({ $0.description })"),
             Example("[].filter { $0.contains(location) }"),
             Example("extension UITableViewCell: ReusableView { }"),
-            Example("extension UITableViewCell: ReusableView {}")
+            Example("extension UITableViewCell: ReusableView {}"),
+            Example("""
+            protocol SomeProtocol {
+               var field: Int {get}
+            }
+            """),
+            Example("""
+            func something(field: Int) {
+               guard field != 0 else {return}
+            }
+            """)
         ],
         triggeringExamples: [
             Example("[].filter(↓{$0.contains(location)})"),
@@ -131,6 +141,15 @@ public struct ClosureSpacingRule: CorrectableRule, ConfigurationProviderRule, Op
                 let cleaned = content.trimmingCharacters(in: .whitespaces)
                 return content != " " + cleaned + " "
             }
+            .filter { range in
+                guard SwiftVersion.current > .fourDotTwo else {
+                    return true
+                }
+
+                let byteOffset = file.stringView.byteOffset(fromLocation: range.location)
+                let structures = file.structureDictionary.structures(forByteOffset: byteOffset)
+                return structures.last?.kind.flatMap(SwiftExpressionKind.init) == .closure
+            }
             .sorted {
                 $0.location < $1.location
             }